its getting louder and louder and happening more now i just took a short drive to cvs and it happed almost every bump, really starting to piss me off

gonna call the dealer tomorrow to see if they know of any causes. I have checked the exhaust by shaking and hitting it with a rubber mallet but it didn't make any noise.
there are no loose cables nothing under the truck is loose i shook and beat everything i didnt find the noise

Took it to the dealer guess what they found... Nothing.. What a supprise. Waste of time, guys trying to blame it on my bed cover but the noise was there before I put that on, then he was complaining of my rims and tires, but thoes were on my old truck and they didn't make any noises. Guess I will continue my search if anyone has any more suggestions please feel free to post them.

Gonna take my rear tires off at lunch today see if anythis is loose behind the wheel.

my reg cab has a weird bang/thud/clunk that happens on bumps going slow. found a spot where i could make it happen repeatedly, as in back and forth going about 1mph, appeared to be some kind of binding in the driveshaft, flipped the shaft so it was back in normal position (had flipped it due to grinding from slip yoke), sound went away, kinda, then came back again but now sounds to be closer to under cab as you describe. may not be same thing at all but something to consider. i have not gone to dealer yet but after the holidays i am going to try to get them to replace the driveshaft like i suggested they looked at over a yr ago.... please keep me posted to anything you find in the event we are experiencing the same issue.

Yea I will keep everyone posted incase more people start to have this issue, if you find a solution let me know as well. I was thinking about taking the driveshaft apart and packing the slip yoke with grease as I saw someone else do it on here, to be honest that's around the area it sounds to be coming from, that would make that kind if noise? Do they come packed with grease?

anyone have any other suggestions? when the back center window is open the sound is very noticeable and i hear it alot more, wish i would of thought about that when i took it to the dealer, the noise happens on pretty much any bump big or small speed bumps, i am stumped, i shake the truck as hard as i can back and forth and no noise jump in the bed no sound seems to only do it when warmed up also. is there a possibility that something in the muffler is loose and only rattles when the metal inside is hot? it really sounds like a tinny sound.

edit: tommrow im going to find a spot where it makes the noise repeadly plant the camera on the ground and keep going back and forth, hopefully i might be able to find it that way?

Fyi just heard through a customer at work that he purchased a 2013 from a dealership that had 13 defective 2013 tacos one was his due to some sort of rear end issue...turns out toyota has switched to a new supplier or something...hes in a big fight with Toyota to swap out his 2013 for a new 2014 when they swith back to their orginal supplier...

Edit: I got some good videos of this noise will post it later, crazy asu can you find out what they outsourced? I feel this truck is built way better than my 2010 reg cab was but this noise is annoying. The noise sounds like the leaf pack idk .

Anyway of testing it? It would give me a reasons for 5100's all around but I'd like to know beforehand, when people describe the slip yoke noise on our trucks how does it sound? Like this? Is it possible for the slip yoke to make this kind of sound?

I found it!! I was installing my hitch today and wile I had my jack out I figured I'd jack up the truck and look, we'll to my surprise, since the leaf pack was not compressed I could look down farther, toward the middle of the pack I saw 2 quarter sized scuff marks where the paint looked to be worn away, took some double sided tape put it on that spot temporarily and guess what... No more clunk. Both sides driver and passenger had the same scuff in the same spot. So I just went to Walmart and picked up some felt pads for the bottom of furniture and I will be putting them in the spots I put the double sided tape. I had figured it might of been the leaf pack so I put tubbing in between but apparently in the wrong spots, if I never had jacked the truck up I would have never saw the marking. Thanks for everyone's help. I'm just glad it was something simple and stupid, pretty sad this is a common issue and the dealer was to stupid to check that. Orwell hope I never have to bring it to them again.